package com.azxc.rapid.auth.utils;

public final class Base64 {
    private static final byte encodingTable[] = { 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,
        82, 83, 84, 85, 86, 87, 88, 89, 90, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,
        112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 43, 47 };
    private static final byte decodingTable[];

    public Base64() {
    }

    public static byte[] encode(byte data[]) {
        int modulus = data.length % 3;
        byte bytes[];
        if (modulus == 0) {
            bytes = new byte[4 * data.length / 3];
        } else {
            bytes = new byte[4 * (data.length / 3 + 1)];
        }
        int dataLength = data.length - modulus;
        int i = 0;
        for (int j = 0; i < dataLength; j += 4) {
            int a1 = data[i] & 0xff;
            int a2 = data[i + 1] & 0xff;
            int a3 = data[i + 2] & 0xff;
            bytes[j] = Base64.encodingTable[a1 >>> 2 & 0x3f];
            bytes[j + 1] = Base64.encodingTable[(a1 << 4 | a2 >>> 4) & 0x3f];
            bytes[j + 2] = Base64.encodingTable[(a2 << 2 | a3 >>> 6) & 0x3f];
            bytes[j + 3] = Base64.encodingTable[a3 & 0x3f];
            i += 3;
        }

        switch (modulus) {
            case 1: // '\001'
                int d1 = data[data.length - 1] & 0xff;
                int b1 = d1 >>> 2 & 0x3f;
                int b2 = d1 << 4 & 0x3f;
                bytes[bytes.length - 4] = Base64.encodingTable[b1];
                bytes[bytes.length - 3] = Base64.encodingTable[b2];
                bytes[bytes.length - 2] = 61;
                bytes[bytes.length - 1] = 61;
                break;

            case 2: // '\002'
                d1 = data[data.length - 2] & 0xff;
                int d2 = data[data.length - 1] & 0xff;
                b1 = d1 >>> 2 & 0x3f;
                b2 = (d1 << 4 | d2 >>> 4) & 0x3f;
                int b3 = d2 << 2 & 0x3f;
                bytes[bytes.length - 4] = Base64.encodingTable[b1];
                bytes[bytes.length - 3] = Base64.encodingTable[b2];
                bytes[bytes.length - 2] = Base64.encodingTable[b3];
                bytes[bytes.length - 1] = 61;
                break;
        }
        return bytes;
    }

    public static byte[] decode(byte data[]) {
        byte bytes[];
        if (data[data.length - 2] == 61) {
            bytes = new byte[(data.length / 4 - 1) * 3 + 1];
        } else if (data[data.length - 1] == 61) {
            bytes = new byte[(data.length / 4 - 1) * 3 + 2];
        } else {
            bytes = new byte[data.length / 4 * 3];
        }
        int i = 0;
        for (int j = 0; i < data.length - 4; j += 3) {
            byte b1 = Base64.decodingTable[data[i]];
            byte b2 = Base64.decodingTable[data[i + 1]];
            byte b3 = Base64.decodingTable[data[i + 2]];
            byte b4 = Base64.decodingTable[data[i + 3]];
            bytes[j] = (byte) (b1 << 2 | b2 >> 4);
            bytes[j + 1] = (byte) (b2 << 4 | b3 >> 2);
            bytes[j + 2] = (byte) (b3 << 6 | b4);
            i += 4;
        }

        if (data[data.length - 2] == 61) {
            byte b1 = Base64.decodingTable[data[data.length - 4]];
            byte b2 = Base64.decodingTable[data[data.length - 3]];
            bytes[bytes.length - 1] = (byte) (b1 << 2 | b2 >> 4);
        } else if (data[data.length - 1] == 61) {
            byte b1 = Base64.decodingTable[data[data.length - 4]];
            byte b2 = Base64.decodingTable[data[data.length - 3]];
            byte b3 = Base64.decodingTable[data[data.length - 2]];
            bytes[bytes.length - 2] = (byte) (b1 << 2 | b2 >> 4);
            bytes[bytes.length - 1] = (byte) (b2 << 4 | b3 >> 2);
        } else {
            byte b1 = Base64.decodingTable[data[data.length - 4]];
            byte b2 = Base64.decodingTable[data[data.length - 3]];
            byte b3 = Base64.decodingTable[data[data.length - 2]];
            byte b4 = Base64.decodingTable[data[data.length - 1]];
            bytes[bytes.length - 3] = (byte) (b1 << 2 | b2 >> 4);
            bytes[bytes.length - 2] = (byte) (b2 << 4 | b3 >> 2);
            bytes[bytes.length - 1] = (byte) (b3 << 6 | b4);
        }
        return bytes;
    }

    public static byte[] decode(String data) {
        byte bytes[];
        if (data.charAt(data.length() - 2) == '=') {
            bytes = new byte[(data.length() / 4 - 1) * 3 + 1];
        } else if (data.charAt(data.length() - 1) == '=') {
            bytes = new byte[(data.length() / 4 - 1) * 3 + 2];
        } else {
            bytes = new byte[data.length() / 4 * 3];
        }
        int i = 0;
        for (int j = 0; i < data.length() - 4; j += 3) {
            byte b1 = Base64.decodingTable[data.charAt(i)];
            byte b2 = Base64.decodingTable[data.charAt(i + 1)];
            byte b3 = Base64.decodingTable[data.charAt(i + 2)];
            byte b4 = Base64.decodingTable[data.charAt(i + 3)];
            bytes[j] = (byte) (b1 << 2 | b2 >> 4);
            bytes[j + 1] = (byte) (b2 << 4 | b3 >> 2);
            bytes[j + 2] = (byte) (b3 << 6 | b4);
            i += 4;
        }

        if (data.charAt(data.length() - 2) == '=') {
            byte b1 = Base64.decodingTable[data.charAt(data.length() - 4)];
            byte b2 = Base64.decodingTable[data.charAt(data.length() - 3)];
            bytes[bytes.length - 1] = (byte) (b1 << 2 | b2 >> 4);
        } else if (data.charAt(data.length() - 1) == '=') {
            byte b1 = Base64.decodingTable[data.charAt(data.length() - 4)];
            byte b2 = Base64.decodingTable[data.charAt(data.length() - 3)];
            byte b3 = Base64.decodingTable[data.charAt(data.length() - 2)];
            bytes[bytes.length - 2] = (byte) (b1 << 2 | b2 >> 4);
            bytes[bytes.length - 1] = (byte) (b2 << 4 | b3 >> 2);
        } else {
            byte b1 = Base64.decodingTable[data.charAt(data.length() - 4)];
            byte b2 = Base64.decodingTable[data.charAt(data.length() - 3)];
            byte b3 = Base64.decodingTable[data.charAt(data.length() - 2)];
            byte b4 = Base64.decodingTable[data.charAt(data.length() - 1)];
            bytes[bytes.length - 3] = (byte) (b1 << 2 | b2 >> 4);
            bytes[bytes.length - 2] = (byte) (b2 << 4 | b3 >> 2);
            bytes[bytes.length - 1] = (byte) (b3 << 6 | b4);
        }
        return bytes;
    }

    static {
        decodingTable = new byte[128];
        for (int i = 65; i <= 90; i++) {
            Base64.decodingTable[i] = (byte) (i - 65);
        }

        for (int i = 97; i <= 122; i++) {
            Base64.decodingTable[i] = (byte) (i - 97 + 26);
        }

        for (int i = 48; i <= 57; i++) {
            Base64.decodingTable[i] = (byte) (i - 48 + 52);
        }

        Base64.decodingTable[43] = 62;
        Base64.decodingTable[47] = 63;
    }
}
